1. Field of the Invention
This invention relates generally to solutions for moving people or items from one location to a higher or lower location along a variable slope without the need for complex leveling mechanisms. More particularly, the invention is directed toward outdoor transportation devices for moving people and things between elevated lake lots and the waterline in a safe and efficient manner along an incline that may vary substantially in slope.
2. Description of Related Art
Water-level lake lots are available for purchase with increasing rarity, and at increasingly inflated prices, substantially reducing the affordability of lake lot vacation or residential homes for all but the wealthy. At the same time, the vast majority of property bordering lakes is undeveloped and has heretofore in many cases been deemed undesirable or even undevelopable because of the grade or obstacles present between the waterline and a suitable location for building a house. The difficulties associated with getting to the focal point of such lotsxe2x80x94the waterxe2x80x94typically prevent the lot from being maximized as a leisure area, or from ever being useable at all for persons with special needs.
Numerous solutions have been advanced to address this problem, none of which are entirely acceptable. Such solutions range from the traditional winding stairs, which can be exhausting or even dangerous for the elderly, infants, and those with special needs, to typically traction cable-lift transport designs. Even these mechanical transports are limited in their application, being by their nature confined to either of two models: (1) a constant slope incline model, or (2) mechanically leveled models that involve moving linkages and machinery to maintain the surface of a transport platform at a relatively level position. In addition to these limitations, the inventor believes these solutions have not obtained the greatest degree of safety that potentially may be developed from alternative solutions such as the invention taught herein.
With the exception of stairs, the most commonly used transportation device in the art of elevated lake lot traversing is the cable-driven hoist platform. Such hoist platforms are exemplified by U.S. Pat. No. 3,168,937 to Redford, et al, which, although here applied to an indoor application, discloses a slope-moving meat cutting platform. Redford employs a constant slope dual rail design having a platform cantilevered between a wheel residing beneath the rail and another wheel disposed above the downward portion of the rail. Additionally, as the slope of the rails is not dependent upon any external factors, Redford shows a constant slope for the rails and includes no leveling mechanism; the teaching of Redford is therefore limited to extremely narrow applications. Redford""s device is cable driven and therefore subject to heightened maintenance and safety concerns of such cable systems.
The art has recognized that not all applications enjoy a static slope, but has grappled with the solution. For instance, devices for ascending along stairs frequently must traverse not only fixed inclines, but also cross over flattened areas where landings are interspersed in the stairway. Designs accommodating variable slopes include the Hein inventions, U.S. Pat. Nos. 5,964,159 and 5,572,930. These stair alternatives incorporate a pair of rails separated by a constant vertical gauge. Leveling is achieved by rotating wheels that lie above and below each rail in a manner that keeps the wheels vertically aligned. Other leveling solutions include elevated transports that level loads strictly by gravity, the loads being suspended from a pivotable linkage, as in U.S. Pat. No. 3,935,822 to Kaufmann. Additional solution concepts for leveling include U.S. Pat. No. 5,069,141 to Ohara, U.S. Pat. No. 4,602,567 to Hedstrom; and U.S. Pat. No. 3,774,548 to Borst, each of which to varying degrees depends upon a hanging load below the level of the rail. The typical hanging load system requires the weight to be centered on the platform; otherwise, the stability and consistency of leveling will be suspect. These systems are subject to undesirable swaying motion, particularly at sudden starts and stops. Additionally of note are solutions for horizontal leveling systems that employ a complex array of tracks and multiple wheels that variously engage and disengage from their respective tracks as movement progresses, such as the xe2x80x9ctraversing elevatorxe2x80x9d described in U.S. Pat. No. 4,821,845.
Other developers have noted difficulty with obtaining reliable and consistent grip between the rails of a transport and the wheels when on a slope. The art has variously attempted to address this difficulty by use of spring loaded wheels, such as those shown in Ohara et al, U.S. Pat. No. 5,069,141, or by gripping teeth, as in U.S. Pat. No. 5,398,617, issued to Deandrea.
None of these prior art systems has maximized the potential available for reliable self leveling traversing devices. It further will be noted by those reasonably skilled in the art that the more complex the leveling, gripping, or safety system becomes, the greater the number of practical issues that arise, such as the expense of manufacture of additional components and the fact that additional components increase the potential for unacceptable failure. The present invention is capable of being practiced without such complexity, though if desired the invention can be practiced in complex embodiments while still maintaining the spirit of the invention.
The following stated objects of the invention are alternative and exemplary objects only, and should not be read as required for the practice of the invention, or as an exhaustive listing of objects accomplished.
As suggested by the foregoing discussion, an exemplary and non-exclusive alternative object of this invention is to provide a transportation device capable of delivering people and articles between a waterline and an elevated lake lot.
A further exemplary and non-exclusive alternative object is to provide a reliable self-leveling transportation device that does not rely solely upon dynamic control or hanging suspension to achieve leveling.
A still further exemplary and non-exclusive alternative object of the invention is to provide a self-leveling transportation device in which, following installation, a failure to level as desired is virtually impossible absent catastrophic damage to the device.
A further exemplary and non-exclusive alternative object of the invention is to provide a transportation device that does not rely upon pulleys or cables.
Yet another exemplary and non-exclusive alternative object of the invention is to provide a transportation device that is unobtrusive and exhibits a small elevation, profile, and footprint on a lake-lot slope.
The invention additionally may allow, in an exemplary and non-exclusive alternative, for a more direct route between a lake lot and the waterline, without the need for a winding path.
The invention is further capable in some exemplary and non-exclusive alternative embodiments of providing an efficient and safe transportation system for adults, children, riders, and bystanders.
The invention is further able to provide in some exemplary and non-exclusive alternative embodiments a lake-lot transportation system that is conveniently located for easy boarding and debarking at nearly ground levels at both the top and bottom of a slope.
The above objects and advantages are neither exhaustive nor individually critical to the spirit and practice of the invention. Other or alternative objects and advantages of the present invention will become apparent to those skilled in the art from the following description of the invention.
The present invention may be described basically as a self leveling transport device with application for delivering people and their accessories between an elevated lake lot and the water line. The transport may be adapted to be low profile against the silhouette of a land slope, increasing attractiveness of the entire surrounding area. The device is able to adjust the xe2x80x9cattitudexe2x80x9d of a load or platform by selectively leveling, or causing to be off level, the load or platform (relative to a horizontal plane, the ground, or other selected orientation or parameter).
Unlike previous rail-mounted systems, the current invention does not require either a constant slope of the incline, or a mechanico-electrical leveling-adjustment system. Rather, within reasonable limits, the rail may be run, if desired, in a straight line (viewed from the water) from the top of an incline to the bottom, hugging the contour of the earth surface the entire distance. This lowers the dangers associated with elevated portions of track that may become necessary for maintaining a constant slope in prior art systems.
The present invention employs a support body platform (which may be a floor bucket, chair, or any other supporting or holding device, including pinchers) connected to a rail by wheels or other traversing members, such as wheels, rollers, bearings, tracks, skids (particularly low-friction skids). One traversing member contacts the rail from below, and a second traversing member contacts the rail from above. Typically, this places the second traversing member both horizontally and vertically offset from and above the first traversing member, when viewed from the side. The platform is connected to the second traversing member and extends over the downslope side of the rail. This creates a cantilevered, or torqued design, in which the center of gravity of the loaded platform is on the opposite side of the second traversing member from the first traversing member, and in which the platform is above the level of the rail. Accordingly, as weight on the platform is increased, the torque increases the effectiveness of friction between traversing members and rail. The present invention can therefore in some embodiments rely wholly upon friction of the traversing members to maintain location upon the rail within preferred operational parameters. The system is therefore amenable to cableless direct drive operation in embodiments using wheels or tracks at the traversing members, in contrast to many prior art devices.
It should be noted that the location of the center of gravity of the platform may change in various states of loading or unloading; it is possible to take advantage of such change by allowing for a shift of the center of gravity to the opposite side of the second traversing member, allowing for easy removal of the platform, maintenance of the traversing members or other equipment, storage, etc.
In order to achieve reliable and durable self-leveling, neither the traversing members nor the angle among the traversing members and the platform needs to be variable; rather each of these can be hard-welded or secured in any other static fashion. Self leveling is effected in the present invention by varying the vertical gauge of the rail (by xe2x80x9cvertical gauge,xe2x80x9d or xe2x80x9cgaugexe2x80x9d hereinafter, is meant the distance from a point on the upper surface of the rail to the closest point on the undersurface of the rail). At any given distance between the traversing members, the cantilever effect causes a wider gauge rail to urge the line between the traversing members to approach perpendicular to the top of the rail. A thinner gauge rail will allow the line between the traversing members to pivot away from perpendicular to the rail, towards an angle that is limited in its acuteness by the configuration of the traversing members (e.g., where wheels are employed as the traversing member, the radial height of the wheels will affect the acuteness of angle obtainable) and the gauge of the rail. Accordingly, the user can determine from the minimum desired gauge of the rail and the configuration (e.g., minimum radius of wheels) of the traversing members, how far off of parallel the line between the traversing members will be from the rail at its most horizontal point. The platform can thereafter be attached to the traversing members in such a way that the fixed angle among the traversing members and the platform results in a horizontally level platform at the most horizontal point on the rail. As the rail becomes more vertically disposed traveling along its length, the platform may be maintained at a horizontal level by widening the gauge of the rail, which will drive the linexe2x80x94and thus the platformxe2x80x94into a changing relationship with the rail to compensate for the increasing slope.
The present invention overcomes the chief limitations of static slope requirement systems, while avoiding complex linkages and mechanical systems.